1. Field of the Invention
The present invention pertains broadly to a sighting device for attachment to an archery bow, and more particularly to such a device incorporating adjusting mechanism by which range and windage corrections can be made to accommodate different target distances and wind conditions.
2. Description of the Prior Art
As archery has become more popular over the years, increasingly sophisticated equipment has been developed for practicing the sport. Among the equipment are various types of sighting devices for mounting upon bows to increase the degree of accuracy with which an arrow is launched toward a target. As an arrow travels from the bow to the target it, of course, follows a trajectory influenced by a number of factors including gravity, arrow weight and velocity, and wind velocity and direction. The effect of these factors, in turn, is a function of the distance travelled by the arrow between the bow and the target. In order to enable a shooter to compensate for different shooting conditions and distances, adjustable sighting devices have been developed wherein the sighting element can be selectively moved vertically and horizontally relative to the bow. As adjusted, the devices during sighting take into account the degree of elevation and horizontal correction necessary to compensate for gravitational and wind effects when the arrow is launched.
Many sighting devices of different types have been proposed as can be seen in the various archery publications, as well as in prior to U.S. patents. In one such type of sighting device as disclosed in U.S. Pat. Nos. 5,174,269 and 5,289,814, for example, a mounting bracket affixed to the bow carries a mounting arm. The sighting device and adjusting mechanism therefore are carried upon the mounting arm some distance from the bow. These devices employ a sight pin or a plurality of sight pins as the viewing device for the archer. A sighting device employing a ring and cross-hair viewer mounted upon a lever and link adjusting mechanism is disclosed in U.S. Pat. No. 4,541,179.
The prior art devices as shown in the aforementioned patents perform satisfactorily. However, devices of the type shown in the latter patent tend to be more complex and relatively difficult to manufacture and maintain. Devices of the type disclosed in the former patents tend to be bulky and cumbersome to use due to the location of the entire adjusting and sighting mechanism at the remote or distal end of the mounting arm. More importantly, as the bow string is released and an arrow is launched, the bow snaps back to its unstressed position, creating a great deal of shock in the bow. This shock is transmitted and amplified through the mounting arm to the relatively massive sighting and adjusting device carried at its remote end. As a result, the devices tend to fail structurally after relatively short periods of use. Thus, while the devices may function very well, they are subject to frequent breakage.